The SURGERY of arthrosis of the subtalar joint, carried out between 9 and 12 years of age, the aim is to restore and maintain the physiological alignment between the talus and the calcaneus during bone maturation.

There are few articles in the literature that talk about the return to sport of pediatric patients after surgery. The aim of the study is to review patients operated on remotely kick heel and describe how they return in their sports (resilience, type of activities carried out, recovery times). The aim of this study is to evaluate the clinical and functional results of patients of age Pediatric treated in the investigator's SC Orthopedics Pediatric Traumatology department for flat feet with "calcaneostop" surgery. The study aims to describe the method of resuming sports activities, analyzing the timing and difficulties declared by patients after surgery, with the help of specific questionnaires.

Inclusion Criteria:

• Idiopathic Flatfoot;
• Surgical treatment with arthrorisis of subtalar joint;
• Follow-up> 48 months
• Completeness of the clinical-radiographic documentation.

Exclusion Criteria:

• Diagnosis of secondary flat valgus foot;
• Flat foot treated with other techniques;
• Incomplete clinical documentation;
• Patients who refuse to undergo the study

The analysis will be performed on pediatric patients undergoing surgical treatment for correction of idiopathic flatfoot in the Orthopedics Pediatric department of the IRCCS Rizzoli Orthopedic Institute in the years 2016-2017.